Previously we have shown that synaptic junctions contain a unique class of glycoproteins which appear to be located on the external surface of the junction within the cleft. Over the past year we have purified and partially characterized these synaptic function glycoproteins. Proteins were solubilized and purified on a Con A affinity column. There are four major classes of glycoproteins as judged by gel electrophoresis. Three of these appear to have the same polypeptide backbone but differ in their carbohydrate composition. We are now in the process of preparing monoclonal antibodies to each type of glycoprotein. We will use these antibodies to evaluate the hypothesis that these glycoproteins are involved in the initial stages of synaptogenesis. These antibodies, as well as others, will be used to examine synapse formation. We are also in the process of developing a tissue culture system using the hippocampus in order to study synapse growth and synaptic plasticity under defined conditions.